The first rule of fairness in film criticism is that you have to judge a movie on its own terms. You can’t say “Schindler’s List” was a bad movie because it wasn’t funny, or that “Tommy Boy” was a bad movie because it wasn’t suspenseful, because those films weren’t TRYING to be those things. You determine what a movie is trying to accomplish, and then you determine whether it succeeded or not.

The problem with this system is when you come to movies like “The In Crowd,” a teen thriller directed by TV-movie director Mary Lambert and starring no one. The film wants to be suspenseful, unpredictable and exciting, but it fails at all of that, coming across instead as lame, cliched, and ridiculous, with ill-defined characters, incredible plot conveniences and general eye-rolling badness. It wants to be taken seriously, but it doesn’t stand a chance.

It succeeds, however, in being marvelously entertaining, deliciously bad, in a thoroughly enjoyable way. Honestly, I haven’t enjoyed a terrible movie this much in ages. It’s fast-paced and breezy and so delightfully stupid that I was never bored with it for a minute.

So does it deserve a good grade or a bad grade? Technically, it should get a bad one, because it fails at what it set out to accomplish. But if you judge it on terms it did NOT set up for itself, as a campy, “guilty-pleasure” film, you gotta admit, it scores high.

The plot: The pert, Barbie-shaped Adrien Williams (Lori Heuring) is let out of the booby hatch after serving some time for being a bit on the obsessive side. Her doctor, Henry Thompson (Daniel Hugh Kelly), gets her a summer job at snooty Cliffmont Country Club, where the queen of the “in crowd,” Brittany Foster (Susan Ward), uses duplicity and deceit to make her part of the group.

Why would Brittany do this? Well, it seems Adrien looks JUST LIKE Brittany’s sister Sandra, who took off a couple years ago and has never come back. Could it be that Brittany, who is a bit more fond of the ladies than I like to see a woman being, and who’s a little obsessive herself, is trying to create a replacement sister? Sure seems that way. Oh, she’s evil, too, but I won’t tell you how.

The title group is meant to be one of those caches of gorgeous people, and they are attractive, but they’re the basic-cable, low-budget kind of attractive — the kind who aren’t quite tan, not completely toned, and who have moles on their cleavage. Not a one of them is very good at acting, either, though none is particularly bad. Lori Heuring, as Adrien, is perhaps even rather good, with a non-skanky Madonna quality about her.

Give them all credit for this: They keep straight faces, even when they’re betting one another for a night with the other’s girlfriend, or staging an elaborate “Scooby-Doo”-style hoax to trap the evil Brittany.

The more I think about it, the more I liked this movie. It’s a terrible piece of work, but man is it ever fun.